Most homes are currently FHA backed loans. In those cases you are playing two strong positions in negotiating the deal; the bank who wants to sell it 'as is', and the FHA lender who wants a home that is in livable condition.
This is why an experienced agent is important in this market. They can help negotiate to get you in to contract, and to address the FHA requirements that are bound to come after you are in contract.
First, in your initial offering you can most likely negotiate anything related to 'health and safety' to be paid for by the seller. These include the HVAC, and possibly the lighting fixtures or appliances. But remember, the seller is looking at the net proceeds that they are to receive from your offer vs. other offers submitted. You may have to increase your price to address these extra expenses.
After you're in contract, and items come up that the FHA wants repaired. You can request those repairs. The seller can agree to fix or they can refuse. If they refuse, we have been successful in increasing the purchase price to cover the repairs, and then having the seller fix them prior to escrow.
It's a real balancing act, being that most bank owned properties try to have you commit to a close of escrow date, or incur penalties-- and the FHA lender throws contingencies at the last minute. So you may have to rediscuss whether penalties will be incurred as delays come up from the FHA requests.
In your circumstances, it's worth a discussion between the listing agent and your buyer's agent to see how best to approach it. A seller is looking for the easiest close at the highest price. You are trying to get a good price on a home that meets your needs, but also addressing requirements of your lender.
Have patience and find a good negotiator. Good luck!